There is a widely used game system that allows three or more players to play one game via a network. A type of this game system advances a game as a unit for a group including a server, or one game terminal selected as a parent node (a server or master node) and two or more predetermined number of game terminals selected as child nodes (client or slave nodes). The communication band (bandwidth) required for the parent node during the game is large, whereas the bandwidth required for the child node is small.
In such a game system, a communication group including plural game terminals is usually provided in each venue, and a group of game terminals that will be used by players is formed across plural venues. Communication between game terminals is performed via a communication path allocated to each communication group (venue). A communication path is shared by game terminals belonging to a communication group that corresponds to the communication path. The amount of the bandwidth required in a communication path will be greatest in a case in which all the game terminals belonging to a communication group corresponding to the communication path are parent nodes. Therefore, communication failures (communication accidents, loss of packets, etc.) that are attributed to insufficient bandwidth in a communication path can be avoided if the bandwidth is allocated in an amount that is equal to or greater than the maximum bandwidth required for the communication path. Doing so, however, severely degrades the efficiency of use of the bandwidth because all the game terminals included in the same communication group simultaneously take the parent node on rare occasions.
Japanese Patent Application Laid-Open Publication No. 2005-137812 proposes a technique in which communication failures are minimized even in an environment in which the bandwidth of each communication path is smaller than the maximum amount of bandwidth required for each communication path. In this technique, game terminals are selected so that the burden is equal among communication groups. According to this technique, undesirable incidents can be avoided, such as a game terminal of a communication group being selected as a parent node, with the communication group corresponding to a communication path having a small amount of remaining bandwidth, or a game terminal of a communication group being selected as the child node, with the communication group corresponding to a communication path having a large amount of remaining bandwidth. Communication failures are therefore minimized.
In the above technique, however, communication errors cannot be completely avoided. To prevent communication failures, the bandwidth of an amount that is equal to or greater than the maximum bandwidth required for each communication path must be allocated as described above. Therefore, the most important challenge is to avoid the degradation in the use efficiency of the bandwidth. To solve this problem, minimizing the maximum amount of bandwidth required is effective. Designing a game so that the communication volume between game terminals is reduced is one way to minimize the maximum amount of bandwidth required. This method, however, degrades the degree of freedom in designing a game.